30 July 2011
Look around you. All over the world, plants are harnessing the sun’s energy to split water molecules, causing oxygen to be released. It’s a process that needs nothing more than light, carbon dioxide, water – and some immensely sophisticated biochemistry on the part of the plants.
For years, scientists have dreamt of creating ‘artificial leaves’ – power sources that would need as few and as simple inputs as real leaves do. These could produce energy for billions of people in parts of the world where electricity is currently unavailable or unreliable.
Now, researchers at MIT, one of the USA’s foremost universities, have taken an important step towards making the dream a reality. Their prototype ‘artificial leaf’ combines a standard silicon solar cell with a catalyst developed by Prof Dan Nocera and his team. When immersed in water and exposed to sunlight, the ‘leaf’ causes bubbles of oxygen to separate out of the water. Again, they’ve learnt from biochemistry to develop their new technology. “The catalyst has the same structure as the leaf’s water-splitting machine but with cobalt instead of manganese,” Prof Nocera explains.
The next step to producing a usable ‘artificial leaf’, the team reports, is to integrate an additional catalyst to bubble out hydrogen molecules. These could then be used to generate electricity or to make fuel for vehicles.
The MIT news office reports: “ultimately, Nocera wants to produce a low-cost device that could be used where electricity is unavailable or unreliable. It would consist of a glass container full of water, with a solar cell with the catalysts on its two sides attached to a divider separating the container into two sections. When exposed to the sun, the electrified catalysts would produce two streams of bubbles — hydrogen on one side, oxygen on the other — which could be collected in two tanks, and later recombined through a fuel cell or other device to generate electricity when needed.”
Read all about it on the MIT news website
Or see Professor Nocera talk about his dream of personalised energy through 'artificial leaves' (discussion of photosyntehsis begins at 12.28)